includes/SearchEngine.php

   1 <?php
   2 # See search.doc
   3
   4 class SearchEngine {
   5         /* private */ var $mUsertext, $mSearchterms;
   6         /* private */ var $mTitlecond, $mTextcond;
   7
   8         var $doSearchRedirects = true;
   9         var $addtoquery = array();
  10         var $namespacesToSearch = array();
  11         var $alternateTitle;
  12         var $all_titles = false;
  13
  14         function SearchEngine( $text )
  15         {
  16                 # We display the query, so let's strip it for safety
  17                 #
  18                 global $wgDBmysql4;
  19                 $lc = SearchEngine::legalSearchChars() . "()";
  20                 if( $wgDBmysql4 ) $lc .= "\"~<>*+-";
  21                 $this->mUsertext = trim( preg_replace( "/[^{$lc}]/", " ", $text ) );
  22                 $this->mSearchterms = array();
  23                 $this->mStrictMatching = true; # Google-style, add '+' on all terms
  24         }
  25
  26         function queryNamespaces()
  27         {
  28                 $namespaces = implode( ",", $this->namespacesToSearch );
  29                 if ($namespaces == "") {
  30                         $namespaces = "0";
  31                 }
  32                 return "AND cur_namespace IN (" . $namespaces . ")";
  33         }
  34
  35         function searchRedirects()
  36         {
  37                 if ( $this->doSearchRedirects ) {
  38                         return "";
  39                 } else {
  40                         return "AND cur_is_redirect=0 ";
  41                 }
  42         }
  43
  44         /* private */ function initNamespaceCheckbox( $i )
  45         {
  46                 global $wgUser, $wgNamespacesToBeSearchedDefault;
  47
  48                 if ($wgUser->getID()) {
  49                         // User is logged in so we retrieve his default namespaces
  50                         return $wgUser->getOption( "searchNs".$i );
  51                 } else {
  52                         // User is not logged in so we give him the global default namespaces
  53                         return $wgNamespacesToBeSearchedDefault[ $i ];
  54                 }
  55         }
  56
  57         # Display the "power search" footer. Does not actually perform the search,
  58         # that is done by showResults()
  59         function powersearch()
  60         {
  61                 global $wgUser, $wgOut, $wgLang, $wgTitle, $wgRequest;
  62
  63                 $search                 = $wgRequest->getText( 'search' );
  64                 $searchx                = $wgRequest->getVal( 'searchx' );
  65                 $listredirs             = $wgRequest->getVal( 'redirs' );
  66
  67                 $ret = wfMsg("powersearchtext"); # Text to be returned
  68                 $tempText = ""; # Temporary text, for substitution into $ret
  69
  70                 if( isset( $_REQUEST["searchx"] ) ) {
  71                         $this->addtoquery["searchx"] = "1";
  72                 }
  73
  74                 # Do namespace checkboxes
  75                 $namespaces = $wgLang->getNamespaces();
  76                 foreach ( $namespaces as $i => $namespace ) {
  77                         # Skip virtual namespaces
  78                         if ( $i < 0 ) {
  79                                 continue;
  80                         }
  81
  82                         $formVar = "ns$i";
  83
  84                         # Initialise checkboxValues, either from defaults or from
  85                         # a previous invocation
  86                         if ( !isset( $searchx ) ) {
  87                                 $checkboxValue = $this->initNamespaceCheckbox( $i );
  88                         } else {
  89                                 $checkboxValue = $_REQUEST[$formVar];
  90                         }
  91
  92                         $checked = "";
  93                         if ( $checkboxValue == 1 ) {
  94                                 $checked = " checked";
  95                                 $this->addtoquery["ns{$i}"] = 1;
  96                                 array_push( $this->namespacesToSearch, $i );
  97                         }
  98                         $name = str_replace( "_", " ", $namespaces[$i] );
  99                         if ( "" == $name ) {
 100                                 $name = wfMsg( "blanknamespace" );
 101                         }
 102
 103                         if ( $tempText !== "" ) {
 104                                 $tempText .= " ";
 105                         }
 106                         $tempText .= "<input type=checkbox value=\"1\" name=\"" .
 107                           "ns{$i}\"{$checked}>{$name}\n";
 108                 }
 109                 $ret = str_replace ( "$1", $tempText, $ret );
 110
 111                 # List redirects checkbox
 112
 113                 $checked = "";
 114                 if ( $listredirs == 1 ) {
 115                         $this->addtoquery["redirs"] = 1;
 116                         $checked = " checked";
 117                 }
 118                 $tempText = "<input type=checkbox value=1 name=\"redirs\"{$checked}>\n";
 119                 $ret = str_replace( "$2", $tempText, $ret );
 120
 121                 # Search field
 122
 123                 $tempText = "<input type=text name=\"search\" value=\"" .
 124                         htmlspecialchars( $search ) ."\" width=80>\n";
 125         $ret = str_replace( "$3", $tempText, $ret );
 126
 127                 # Searchx button
 128
 129                 $tempText = "<input type=submit name=\"searchx\" value=\"" .
 130                   wfMsg("powersearch") . "\">\n";
 131                 $ret = str_replace( "$9", $tempText, $ret );
 132
 133                 global $wgScript;
 134                 $ret = "<br><br>\n<form id=\"powersearch\" method=\"get\" " .
 135                   "action=\"$wgScript\">\n{$ret}\n</form>\n";
 136
 137                 if ( isset ( $searchx ) ) {
 138                         if ( ! $listredirs ) {
 139                                 $this->doSearchRedirects = false;
 140                         }
 141                 }
 142                 return $ret;
 143         }
 144
 145         # Perform the search and construct the results page
 146         function showResults()
 147         {
 148                 global $wgUser, $wgTitle, $wgOut, $wgLang, $wgDisableTextSearch;
 149                 global $wgInputEncoding;
 150                 $fname = "SearchEngine::showResults";
 151
 152                 $search = $_REQUEST['search'];
 153
 154                 $powersearch = $this->powersearch(); /* Need side-effects here? */
 155
 156                 $wgOut->setPageTitle( wfMsg( "searchresults" ) );
 157                 $q = wfMsg( "searchquery", htmlspecialchars( $this->mUsertext ) );
 158                 $wgOut->setSubtitle( $q );
 159                 $wgOut->setArticleRelated( false );
 160                 $wgOut->setRobotpolicy( "noindex,nofollow" );
 161
 162                 $sk = $wgUser->getSkin();
 163                 $header = wfMsg( "searchresulttext", $sk->makeKnownLink(
 164                   wfMsg( "searchhelppage" ), wfMsg( "searchingwikipedia" ) ) );
 165                 $wgOut->addHTML( $header );
 166
 167                 $this->parseQuery();
 168                 if ( "" == $this->mTitlecond || "" == $this->mTextcond ) {
 169                         $wgOut->addHTML( "<h2>" . wfMsg( "badquery" ) . "</h2>\n" .
 170                           "<p>" . wfMsg( "badquerytext" ) );
 171                         return;
 172                 }
 173                 list( $limit, $offset ) = wfCheckLimits( 20, "searchlimit" );
 174
 175                 $searchnamespaces = $this->queryNamespaces();
 176                 $redircond = $this->searchRedirects();
 177
 178                 if ( $wgDisableTextSearch ) {
 179                         $wgOut->addHTML( wfMsg( "searchdisabled" ) );
 180                         $wgOut->addHTML( wfMsg( "googlesearch", htmlspecialchars( $search ), $GLOBALS['wgInputEncoding'] ) );
 181                 } else {
 182                         $sql = "SELECT cur_id,cur_namespace,cur_title," .
 183                           "cur_text FROM cur,searchindex " .
 184                           "WHERE cur_id=si_page AND {$this->mTitlecond} " .
 185                           "{$searchnamespaces} {$redircond}" .
 186                           "LIMIT {$offset}, {$limit}";
 187                         $res1 = wfQuery( $sql, DB_READ, $fname );
 188                         $num = wfNumRows($res1);
 189
 190                         $sk = $wgUser->getSkin();
 191                         $text = "";
 192
 193                         $this->parseQuery();
 194                         if ( "" == $this->mTitlecond || "" == $this->mTextcond ) {
 195                                 $wgOut->addHTML( "<h2>" . wfMsg( "badquery" ) . "</h2>\n" .
 196                                   "<p>" . wfMsg( "badquerytext" ) );
 197                                 return;
 198                         }
 199                         list( $limit, $offset ) = wfCheckLimits( 20, "searchlimit" );
 200
 201                         $searchnamespaces = $this->queryNamespaces();
 202                         $redircond = $this->searchRedirects();
 203
 204                         $sql = "SELECT cur_id,cur_namespace,cur_title," .
 205                           "cur_text FROM cur,searchindex " .
 206                           "WHERE cur_id=si_page AND {$this->mTitlecond} " .
 207                           "{$searchnamespaces} {$redircond}" .
 208                           "LIMIT {$offset}, {$limit}";
 209                         $res1 = wfQuery( $sql, DB_READ, $fname );
 210                         $num = wfNumRows($res1);
 211
 212                         $sql = "SELECT cur_id,cur_namespace,cur_title," .
 213                           "cur_text FROM cur,searchindex " .
 214                           "WHERE cur_id=si_page AND {$this->mTextcond} " .
 215                           "{$searchnamespaces} {$redircond} " .
 216                           "LIMIT {$offset}, {$limit}";
 217                         $res2 = wfQuery( $sql, DB_READ, $fname );
 218                         $num = $num + wfNumRows($res2);
 219
 220                         if ( $num == $limit ) {
 221                           $top = wfShowingResults( $offset, $limit);
 222                         } else {
 223                           $top = wfShowingResultsNum( $offset, $limit, $num );
 224                         }
 225                         $wgOut->addHTML( "<p>{$top}\n" );
 226
 227                         # For powersearch
 228
 229                         $a2l = "" ;
 230                         $akk = array_keys( $this->addtoquery ) ;
 231                         foreach ( $akk AS $ak ) {
 232                                 $a2l .= "&{$ak}={$this->addtoquery[$ak]}" ;
 233                         }
 234
 235                         $sl = wfViewPrevNext( $offset, $limit, "",
 236                           "search=" . wfUrlencode( $this->mUsertext ) . $a2l );
 237                         $wgOut->addHTML( "<br>{$sl}\n" );
 238
 239                         $foundsome = false;
 240
 241                         if ( 0 == wfNumRows( $res1 ) ) {
 242                                 $wgOut->addHTML( "<h2>" . wfMsg( "notitlematches" ) .
 243                                   "</h2>\n" );
 244                         } else {
 245                                 $foundsome = true;
 246                                 $off = $offset + 1;
 247                                 $wgOut->addHTML( "<h2>" . wfMsg( "titlematches" ) .
 248                                   "</h2>\n<ol start='{$off}'>" );
 249
 250                                 while ( $row = wfFetchObject( $res1 ) ) {
 251                                         $this->showHit( $row );
 252                                 }
 253                                 wfFreeResult( $res1 );
 254                                 $wgOut->addHTML( "</ol>\n" );
 255                         }
 256
 257                         if ( 0 == wfNumRows( $res2 ) ) {
 258                                 $wgOut->addHTML( "<h2>" . wfMsg( "notextmatches" ) .
 259                                   "</h2>\n" );
 260                         } else {
 261                                 $foundsome = true;
 262                                 $off = $offset + 1;
 263                                 $wgOut->addHTML( "<h2>" . wfMsg( "textmatches" ) . "</h2>\n" .
 264                                   "<ol start='{$off}'>" );
 265                                 while ( $row = wfFetchObject( $res2 ) ) {
 266                                         $this->showHit( $row );
 267                                 }
 268                                 wfFreeResult( $res2 );
 269                                 $wgOut->addHTML( "</ol>\n" );
 270                         }
 271                         if ( ! $foundsome ) {
 272                                 $wgOut->addHTML( "<p>" . wfMsg( "nonefound" ) . "\n" );
 273                         }
 274                         $wgOut->addHTML( "<p>{$sl}\n" );
 275                         $wgOut->addHTML( $powersearch );
 276                 }
 277         }
 278
 279         function legalSearchChars()
 280         {
 281                 $lc = "A-Za-z_'0-9\\x80-\\xFF\\-";
 282                 return $lc;
 283         }
 284
 285         function parseQuery()
 286         {
 287                 global $wgDBminWordLen, $wgLang, $wgDBmysql4;
 288
 289                 if( $wgDBmysql4 ) {
 290                         # Use cleaner boolean search if available
 291                         return $this->parseQuery4();
 292                 }
 293
 294                 $lc = SearchEngine::legalSearchChars() . "()";
 295                 $q = preg_replace( "/([()])/", " \\1 ", $this->mUsertext );
 296                 $q = preg_replace( "/\\s+/", " ", $q );
 297                 $w = explode( " ", strtolower( trim( $q ) ) );
 298
 299                 $last = $cond = "";
 300                 foreach ( $w as $word ) {
 301                         $word = $wgLang->stripForSearch( $word );
 302                         if ( "and" == $word || "or" == $word || "not" == $word
 303                           || "(" == $word || ")" == $word ) {
 304                                 $cond .= " " . strtoupper( $word );
 305                                 $last = "";
 306                         } else if ( strlen( $word ) < $wgDBminWordLen ) {
 307                                 continue;
 308                         } else if ( FulltextStoplist::inList( $word ) ) {
 309                                 continue;
 310                         } else {
 311                                 if ( "" != $last ) { $cond .= " AND"; }
 312                                 $cond .= " (MATCH (##field##) AGAINST ('" .
 313                                   wfStrencode( $word ). "'))";
 314                                 $last = $word;
 315                                 array_push( $this->mSearchterms, "\\b" . $word . "\\b" );
 316                         }
 317                 }
 318                 if ( 0 == count( $this->mSearchterms ) ) { return; }
 319
 320                 $this->mTitlecond = "(" . str_replace( "##field##",
 321                   "si_title", $cond ) . " )";
 322
 323                 $this->mTextcond = "(" . str_replace( "##field##",
 324                   "si_text", $cond ) . " AND (cur_is_redirect=0) )";
 325         }
 326
 327         function parseQuery4()
 328         {
 329                 global $wgLang;
 330                 $lc = SearchEngine::legalSearchChars();
 331                 $searchon = "";
 332                 $this->mSearchterms = array();
 333
 334                 # FIXME: This doesn't handle parenthetical expressions.
 335                 if( preg_match_all( '/([-+<>~]?)(([' . $lc . ']+)(\*?)|"[^"]*")/',
 336                           $this->mUsertext, $m, PREG_SET_ORDER ) ) {
 337                         foreach( $m as $terms ) {
 338                                 if( $searchon !== "" ) $searchon .= " ";
 339                                 if( $this->mStrictMatching && ($terms[1] == "") ) {
 340                                         $terms[1] = "+";
 341                                 }
 342                                 $searchon .= $terms[1] . $wgLang->stripForSearch( $terms[2] );
 343                                 if( $terms[3] ) {
 344                                         $regexp = preg_quote( $terms[3] );
 345                                         if( $terms[4] ) $regexp .= "[0-9A-Za-z_]+";
 346                                 } else {
 347                                         $regexp = preg_quote( str_replace( '"', '', $terms[2] ) );
 348                                 }
 349                                 $this->mSearchterms[] = $regexp;
 350                         }
 351                         wfDebug( "Would search with '$searchon'\n" );
 352                         wfDebug( "Match with /\b" . implode( '\b|\b', $this->mSearchterms ) . "\b/\n" );
 353                 } else {
 354                         wfDebug( "Can't understand search query '$this->mUsertext'\n" );
 355                 }
 356
 357                 $searchon = wfStrencode( $searchon );
 358                 $this->mTitlecond = " MATCH(si_title) AGAINST('$searchon' IN BOOLEAN MODE)";
 359                 $this->mTextcond = " (MATCH(si_text) AGAINST('$searchon' IN BOOLEAN MODE) AND cur_is_redirect=0)";
 360         }
 361
 362         function showHit( $row )
 363         {
 364                 global $wgUser, $wgOut;
 365
 366                 $t = Title::makeName( $row->cur_namespace, $row->cur_title );
 367                 $sk = $wgUser->getSkin();
 368
 369                 $contextlines = $wgUser->getOption( "contextlines" );
 370                 if ( "" == $contextlines ) { $contextlines = 5; }
 371                 $contextchars = $wgUser->getOption( "contextchars" );
 372                 if ( "" == $contextchars ) { $contextchars = 50; }
 373
 374                 $link = $sk->makeKnownLink( $t, "" );
 375                 $size = wfMsg( "nbytes", strlen( $row->cur_text ) );
 376                 $wgOut->addHTML( "<li>{$link} ({$size})" );
 377
 378                 $lines = explode( "\n", $row->cur_text );
 379                 $pat1 = "/(.*)(" . implode( "|", $this->mSearchterms ) . ")(.*)/i";
 380                 $lineno = 0;
 381
 382                 foreach ( $lines as $line ) {
 383                         if ( 0 == $contextlines ) { break; }
 384                         --$contextlines;
 385                         ++$lineno;
 386                         if ( ! preg_match( $pat1, $line, $m ) ) { continue; }
 387
 388                         $pre = $m[1];
 389                         if ( 0 == $contextchars ) { $pre = "..."; }
 390                         else {
 391                                 if ( strlen( $pre ) > $contextchars ) {
 392                                         $pre = "..." . substr( $pre, -$contextchars );
 393                                 }
 394                         }
 395                         $pre = wfEscapeHTML( $pre );
 396
 397                         if ( count( $m ) < 3 ) { $post = ""; }
 398                         else { $post = $m[3]; }
 399
 400                         if ( 0 == $contextchars ) { $post = "..."; }
 401                         else {
 402                                 if ( strlen( $post ) > $contextchars ) {
 403                                         $post = substr( $post, 0, $contextchars ) . "...";
 404                                 }
 405                         }
 406                         $post = wfEscapeHTML( $post );
 407                         $found = wfEscapeHTML( $m[2] );
 408
 409                         $line = "{$pre}{$found}{$post}";
 410                         $pat2 = "/(" . implode( "|", $this->mSearchterms ) . ")/i";
 411                         $line = preg_replace( $pat2,
 412                           "<font color='red'>\\1</font>", $line );
 413
 414                         $wgOut->addHTML( "<br><small>{$lineno}: {$line}</small>\n" );
 415                 }
 416                 $wgOut->addHTML( "</li>\n" );
 417         }
 418
 419         function goResult()
 420         {
 421                 global $wgOut, $wgDisableTextSearch;
 422                 $fname = "SearchEngine::goResult";
 423
 424                 $search         = $_REQUEST['search'];
 425
 426                 # First try to go to page as entered.
 427                 #
 428                 $t = Title::newFromText( $search );
 429
 430                 # If the string cannot be used to create a title
 431                 if( false == $t ){
 432                         $this->showResults();
 433                         return;
 434                 }
 435
 436                 if ( 0 != $t->getArticleID() ) {
 437                         $wgOut->redirect( $t->getFullURL() );
 438                         return;
 439                 }
 440
 441                 # Now try all lower case (i.e. first letter capitalized)
 442                 #
 443                 $t = Title::newFromText( strtolower( $search ) );
 444                 if ( 0 != $t->getArticleID() ) {
 445                         $wgOut->redirect( $t->getFullURL() );
 446                         return;
 447                 }
 448
 449                 # Now try capitalized string
 450                 #
 451                 $t = Title::newFromText( ucwords( strtolower( $search ) ) );
 452                 if ( 0 != $t->getArticleID() ) {
 453                         $wgOut->redirect( $t->getFullURL() );
 454                         return;
 455                 }
 456
 457                 # Now try all upper case
 458                 #
 459                 $t = Title::newFromText( strtoupper( $search ) );
 460                 if ( 0 != $t->getArticleID() ) {
 461                         $wgOut->redirect( $t->getFullURL() );
 462                         return;
 463                 }
 464
 465                 # No match, generate an edit URL
 466                 $t = Title::newFromText( $this->mUsertext );
 467                 $wgOut->addHTML( wfMsg("nogomatch", $t->escapeLocalURL( "action=edit" ) ) . "\n<p>" );
 468
 469                 # Try a fuzzy title search
 470                 $anyhit = false;
 471                 global $wgDisableFuzzySearch;
 472                 if(! $wgDisableFuzzySearch ){
 473                         foreach( array(NS_MAIN, NS_WP, NS_USER, NS_IMAGE, NS_MEDIAWIKI) as $namespace){
 474                                 $anyhit |= SearchEngine::doFuzzyTitleSearch( $search, $namespace );
 475                         }
 476                 }
 477
 478                 if( ! $anyhit ){
 479                         return $this->showResults();
 480                 }
 481         }
 482
 483         /* static */ function doFuzzyTitleSearch( $search, $namespace ){
 484                 global $wgLang, $wgOut;
 485                 $sstr = ucfirst($search);
 486                 $sstr = str_replace(" ", "_", $sstr);
 487                 $fuzzymatches = SearchEngine::fuzzyTitles( $sstr, $namespace );
 488                 $fuzzymatches = array_slice($fuzzymatches, 0, 10);
 489                 $slen = strlen( $search );
 490                 $wikitext = "";
 491                 foreach($fuzzymatches as $res){
 492                         $t = str_replace("_", " ", $res[1]);
 493                         $tfull = $wgLang->getNsText( $namespace ) . ":$t|$t";
 494                         if( $namespace == NS_MAIN )
 495                                 $tfull = "$t";
 496                         $distance = $res[0];
 497                         $closeness = (strlen( $search ) - $distance) / strlen( $search );
 498                         $percent = intval( $closeness * 100 ) . "%";
 499                         $stars = str_repeat("*", ceil(5 * $closeness) );
 500                         $wikitext .= "* [[$tfull]] $percent ($stars)\n";
 501                 }
 502                 if( $wikitext ){
 503                         if( $namespace != NS_MAIN )
 504                                 $wikitext = "=== " . $wgLang->getNsText( $namespace ) . " ===\n" . $wikitext;
 505                         $wgOut->addWikiText( $wikitext );
 506                         return true;
 507                 }
 508                 return false;
 509         }
 510
 511         /* static */ function fuzzyTitles( $sstr, $namespace = NS_MAIN ){
 512                 $span = 0.10; // weed on title length before doing levenshtein.
 513                 $tolerance = 0.35; // allowed percentage of erronous characters
 514                 $slen = strlen($sstr);
 515                 $tolerance_count = ceil($tolerance * $slen);
 516                 $spanabs = ceil($slen * (1 + $span)) - $slen;
 517                 # print "Word: $sstr, len = $slen, range = [$min, $max], tolerance_count = $tolerance_count<BR>\n";
 518                 $result = array();
 519                 $cnt = 0;
 520                 for( $i=0; $i <= $spanabs; $i++ ){
 521                         $titles = SearchEngine::getTitlesByLength( $slen + $i, $namespace );
 522                         if( $i != 0) {
 523                                 $titles = array_merge($titles, SearchEngine::getTitlesByLength( $slen - $i, $namespace ) );
 524                         }
 525                         foreach($titles as $t){
 526                                 $d = levenshtein($sstr, $t);
 527                                 if($d < $tolerance_count)
 528                                         $result[] = array($d, $t);
 529                                 $cnt++;
 530                         }
 531                 }
 532                 usort($result, "SearchEngine_pcmp");
 533                 return $result;
 534         }
 535
 536         /* static */ function getTitlesByLength($aLength, $aNamespace = 0){
 537                 global $wgMemc, $wgDBname;
 538
 539                 // to avoid multiple costly SELECTs in case of no memcached
 540                 if( $this->all_titles ){
 541                         if( isset( $this->all_titles[$aLength][$aNamespace] ) ){
 542                                 return $this->all_titles[$aLength][$aNamespace];
 543                         } else {
 544                                 return array();
 545                         }
 546                 }
 547
 548                 $mkey = "$wgDBname:titlesbylength:$aLength:$aNamespace";
 549                 $mkeyts = "$wgDBname:titlesbylength:createtime";
 550                 $ts = $wgMemc->get( $mkeyts );
 551                 $result = $wgMemc->get( $mkey );
 552
 553                 if( time() - $ts < 3600 ){
 554                         // note: in case of insufficient memcached space, we return
 555                         // an empty list instead of starting to hit the DB.
 556                         return is_array( $result ) ? $result : array();
 557                 }
 558
 559                 $wgMemc->set( $mkeyts, time() );
 560
 561                 $res = wfQuery("SELECT cur_title, cur_namespace FROM cur", DB_READ);
 562                 $titles = array(); // length, ns, [titles]
 563                 while( $obj = wfFetchObject( $res ) ){
 564                         $title = $obj->cur_title;
 565                         $ns = $obj->cur_namespace;
 566                         $len = strlen( $title );
 567                         $titles[$len][$ns][] = $title;
 568                 }
 569                 foreach($titles as $length => $length_arr){
 570                         foreach($length_arr as $ns => $title_arr){
 571                                 $mkey = "$wgDBname:titlesbylength:$length:$ns";
 572                                 $wgMemc->set( $mkey, $title_arr, 3600 * 24 );
 573                         }
 574                 }
 575                 $this->all_titles = $titles;
 576                 if( isset( $titles[$aLength][$aNamespace] ) )
 577                         return $titles[$aLength][$aNamespace];
 578                 else
 579                         return array();
 580         }
 581 }
 582
 583 /* private static */ function SearchEngine_pcmp($a, $b){ return $a[0] - $b[0]; }
 584
 585 ?>